Expansion valve regulating mechanism for refrigerating systems



Oct. 30, 1934. w Q HILL 1,978,709

EXPANSION VALVE REGULATINGMECHANISM FOR REFRIGERATING SYSTEMS Filedoct. 1. 1951 Patented 30, 1934 EXPANSIN VALVE REGULATING MECHA- NISM FORBEFRIGEBATING SYSTEMS.

g william c. mu, Denham, men. application october 1, 1931, serial No.566,285

14 claim..

This invention relates to expansion valves oi the type commonly used inmechanical refrigeration systems, and has for one of its objectsprovision of a greatly improved expansion valve 6 having especialutility when arranged to independently control the supply of refrigerantto one of a plurality of evaporators all oi' which are incorporated inthe same refrigerating circuit, that is, supplied by the same compressorwith 10 refrigerant which returns thereto.

Another object of this invention is the provision of such an expansionvalve as will maintain one of a plurality of so arranged cooling unitsthe .temperature of the other units, and semiindependently of theback-pressure in the evaporator. As is well known, most of suchexpansion valves, when incorporated in a mechanical re- !rigeratingcircuit of the usual type comprising a compressor, condenser, expansionvalve and evaporator, rely for their operation upon the rise and fall ofback-pressure generated in the evaporator or expansion tank, by thepresence therein or absence therefrom of sumcient gase` ou's refrigerantat sumciently high pressure to permit closure or opening of the valveunder' the influence o1 one of a pair of opposed springs or the like.When a number of evaporators, 3' each having its own expansion valve,are suphowever, it becomes a practical impossibility. to

such evaporators at variant tempera- Y tures (which is frequently adesideratum) as 'theV back pressure in such unitstends to equalize,

a dueto their connection to. a common return line.

It is an object of this invention to so control the operation of eachexpansion valve, indei pendently of the back pressure in its evaporator,that such units may be -maintained at any desired variant temperature.

It is also an object of this invention to provide"improved electricalcontrolling meansvfor the operation of an expansion valve.

i AA still fm'ther object of this invention lies in the provision ofmeans for preventing undesired opening of the expansion valve of arefrigerating system when the pressure on its low side falls below thereduced point at whichthe valve normally opens.

Other objects and advantages will be apparent -from the followingdescription, wherein refer enceismadetotheaccompanyingdrawing Y.illustrating preferred embodiments of my inven-` sstiornand whereinsimilar reference numerals at any desired temperature,V independently oiplied from -a single compressor and condenser,-

' designate similar parts throughout the several views.

In the drawing:

Figure 1 is a fragmentary schematic of a refrigerating system, yshowinga plurality of' cooling units connected to refrigerant supply and returnlines.

Figure 2 is a sectional and partly diagrammatic view of an expansionvalve incorporating one form of my invention.

Figures 3, 4, 5, 6, and 'I are views similar to Figure 2 of expansionvalves incorporating somewhat modiiied forms of my invention.

Referring now to the drawing, reference character l0 represents arefrigerant supply pipe, on the high side of a vcirculatoryrefrigerating system, and 11 a. plurality of expansion valves and their'appurtenant pipes` located in suitable and desired positionstherealong, for controlling the supply of refrigerant to separateevaporators- Since this invention concerns itself entirely withlexpansion valve constructions. no attempt is made to illustrate'ordescribe in detail the other portions of a refrigerating system, furtherthan is necessary to render clear the present disclosure. It is to beunderstood moreover that 'such refrigerating apparatus may be of any de-Vsired form and construction, and that my improved expansion valve might'also be adapted to numerous other uses. Y v

In the construction shown in Figure 2, the valve 12 is normally/intainedin opened position by the compression spring 13, which urges downwardlythe diaphragm 14,.the central oiset sylphon portion 15 of which isengaged by the stem 16 of the valve 12. The valve is urged toward closedposition by the spring 17, which is of course weaker than the spring 13.Refrigerant enters the chamber 18 through the supply tube 19, which isconnected to the main supply line 10, and passes through-the valveorifice 20 to the chamber 21 immediately beneath the diaphragm 14,whence it is conducted tothe evaporator by the tube 22. It will bevobvious that when the pressure-rises sufficiently in the 10 chamber 21,due tothe boiling of the refrigerant in the evaporator, the tendency ofthe thus generated back pressure is to lift the diaphragm 14 againstthe'force o'f the spring 13, which-in an ordinary expansion valveconstruction would l as the pressure in the chamber 21 falls sumciently,the valve reopens, as the spring 13 then overcomes the opposing force ofthe spring 17. This is frequently undesirable, as it may be desired tomaintain the evaporator controlled by this particular expansion valve ata higher temperature than the possible To prevent reopening of thevalve, despite the decreasing back-pressure, until a desired temperaturehasibeen attained, I provide the diaphragm 14 with the above mentionedoset exible bellows or sylphon portion 15, against which the valve stemengages. A sleeve 23 surrounds such sylphon portion, and its bottom issecured to the diaphragm. The sleeve is provided with an end can v24 atits upper extremity, which may be screw-threaded therein to permitadjustment, as shown in Figure 2. The upper end of the ilexible bellowsportion 15 of thediaphragm 14 is closed by a relatively stiff bufferplate 25, which receives the thrust of the valve stem 16. It Will beapparent that, due to the flexibility of the bellows 15, in order toopen the valve, or to maintain the same in opened position, the downwardmovement of the spring 13 must be transmitted through the buffer plate25, as the downward force exerted by spring 13 on the main diaphragm 14is rendered relatively ineffective by the interposition of the bellows15 between the diaphragm and-valve stem.

Between the end cap 24 and the bull'er plate25 y,

incorporated in the thrust-transmitting member is adapted when heated toswell the plates 26 sufficiently to establish contact between plates 24and 25, thereby rendering the spring 13 operative to open the expansionvalve, provided the pressure in the chamber 21 is sufliciently reduced.The exible conductors 29 may connect the heating 'element with athermostat (not shown) in the refrigerated zone, or other suitableoutside controlling means, `automatic or otherwise. If desired pads orspacers 45 formed of material of poor thermal conductivity may be usedto separate and insulate the buffer plate 25 and the adjacent one of theplates 26 on the one hand and the end cap 24 and another one of theplates 26 on the other side.

It will be apparent that as long as the heating element 28 is energizedand the plates 26 distended, ,the valve will function in the normalmanner, but that when the plates of the thrusttransmitting member areallowed to collapse, due to the de-energization of the heating element,the valve will remain closed, since the thrust of the spring 13 is thenineffective to open it. yIn this manner a thermostat may be arranged toso control the functioning of the expansiotn valve that the valve may beallowed to remain closed, independently of falling pressure on the lowside, until the temperature in the refrigerated zone reaches any desiredpoint at which the thermostat may be set; and this though the evaporatormay be one of several connected to a common return line, as 30, Figure1.

In Figures 3, 4, 5, 6 and 7 are illustrated somewhat modified forms ofmy invention, all of which are productive of similar results. In Figure3 is shown an expansion valve normally controlled in the conventionalmanner by a thermostat comprising the bulb 3l, connected tube 32 andbellows 33, in which may be trapped a suitable volatile fluid in thewell known manner. The thrust of the bellows 33 is transmitted to thethrust plate 14 through the crown cap 24g. The thrust plate 14a will beseen to be centrally provided with an oilset ilexible sylphon portion15a, similar to the portion 15 previously described, but extending inthe opposite direction. A relatively stii buer plate 25a similarlycloses the end of the sylphon portion and bears against the stem 161i. Athrust-transmitting member may be provided partially housed within thesylphon portion 15, and comprising a substantially cylindrical cuppedportion 27a closed at its upper end by a distortable outwardly convexedmetallic cap 26a. A heating element 28' is similarly `provided withinthe thrusttransmitting member, which, when heated, is

adapted to expand the air or other fluid contents of thethrust-transmitting member, to upwardly distend the cap 269. It will beseen that the'pressure exerted by the bellows 33 can only be madeeffective to` open or maintain in open position the valve 12a when theheating element 28 is energized and the thrust-transmitting memberexpanded to operatively connect the buffer plate 25=l and cap 24-, uponwhich the thrust of the bellows is directly imposed. The exible leads 29may connect the electrical heating element with any suitable outsidecontrolling means, in the manner set forth in connection with the firstdescribed embodiment, and it will be seen that when the heating elementis energized the operation of this form of my invention is also similarto that of an ordinary expansion valve; and accordingly need not againbe described. The parts of such conventional portions of the device arenumbered similarly to those of the first described embodiment, with theaddition of a exponents to the reference characters. The constructionshown in Figure 4 di'ers from that of Figure 3 principally in that thecombined chamber 33b and diaphragm 14b serve the function performed, asto the construction shown in Figure 3 by the thrust plate 148L and thebellows Figure 4 shows another somewhat modied form of my invention inwhich a conventional type of thermostatic control may be provided,governed by the bulb 31", tube 32b and chamber 33', which is closed bythe diaphragm 14b to which the chamber is sealed by the ilexible bellows34. Such thermostatic controlling means may be rendered normallyineffective to open the expansion valve in a similar fashion, as bycentrally providing the diaphragm 14h with an o'set flexible portionlb'closed by a buffer cap 25h, against which the valve stem 16b engages.Secured to and movable with the diaphragm 14b surrounding the sylphon15b is a light but rigid housing 23h, which is provided with an enlargedcylindrical upper extremity serving as a casing for the bellows 27h,which constitutes an auxiliary thermostatic element and is connected bymeans of the tube 29'J to the bulb 35. The bellows 27b will be seenin'this embodiment to upon the diaphragm, exerted within thethermostatic phamber 33 by engagement of the end caps 26 ofthe bellowswith theo buffer plate 25" and the upper' end of the housing 23, is thelexpansion valve operable in 4the-normal manner,

that is, under the control of the thermostatic bulb 31" as to theopening of the valve.

As shown in Figure 5, the expansion valve may be controlled by athermostatic bulb 31, which is in turn controlled by an electrical heat-The thrust of the spring 13 is 'in this embodiment imposed directly uponthediaphragm 14, but is rendered ineilective to open the valvel undernormal conditions by the offset sylphon portion 15, against the bufferplate of which the valvel stem 16 engages. 'Ihe thermostatic chamber 33may. be closed by the same sylphon. 15, as there shown. and is connectedto the bulb 31 4by the tube 32. They end or buiIer plate 25 vof thesylphon is normally urged upwardly and away from the end of thevalvestem by the coil spring 36. This spring may be positioned by an upwardlyprojecting boss or sleeve portion 37 carried by the diaphragm 14. Thefluid within the connected bulb 31, tube 32 and chamber 33 is of suchquantity and volatility that it cannot expand suillciently under Vnormaloperating conditions to move the plate 25 downwardly into engagementwith the valve stem, to permit opening of the valve 12, except whenrtheheating element 28 is energized to vsuillciently expand the con- `tentsof the thermostatic system. It -will of course be obvious that theenergization or otherwise of the bulb 31c may be regulated in the '38formed in the' thrust plate 14d.

same manner as that provided as tov thebulbl v35 Vin the constructionshown in Figure 4.

The modiiled form, shown in Figure 6 is also electrically controlled,and-the heating element 18 may be housed in a cupped central portion Thethrust plate is connected to the housing 39 ot the valve by a ilexiblebellows 40, and the downward force of the spring 13, tending to open thevalve .12

againstthe tension'of the spring 17, must be exerted through the sylphon15 and its buffer cap 25. l'Ihe ilexibility of the sylphon is'such',however, that sumcient pressure cannot be transmitted to accomplishopening or maintenance of the valve iny open Position unless the` air'or'other fluid trapped' between thesyl- 'phon 15 and cupped portion 38 ofthe dia-- phragm is expanded, as by energiaation ofthe heating element18. The plate 25 is normally urged away from the end of the valve stemby the spring 30; which is 'supported by a spider or cupped support 37secured to the thrust plate 14. Actual separation of the plate 25 andthe valve stem 16 may occur, dependent 'upon the degree of energizationof the heating element 18. The operation ot the remainder of thisembodiment of my invention seen to be analogous to the operation of thements previously described.

As shown in Figure 7, a member in the nature' of a wedge, ale-26 may beinterposed-between theendof-thevalvestemandthepressureresponsivediaphragm 14%', which may be moved tothe left. as viewed inthatll'igure, to so separate the complementarily wedge-shaped butler 25ecarried by the diaphragm 14 from the valve stem as to render the latternon-actuatable by the former. 'I'he wedge `member 26 may be operable inany suitable manner, analogousv to one of those previously described, asby the bellows 27 connected thereto by the link 43, and the likefunctioning of the device to those previously described will beapparent.

As to eachof the suggested modified forms shown in .Figures v3 to 'linclusive, pads of insulating or semi-insulating material similar to,the pads described as to, the construction shown in Figure 2 may, ifdesired, be used to adequately separate the heat-energized parts fromthe adjacent cap and builer plates.

It will be apparent that by employing one or more of my improvedexpansion valves provided with Iauxiliary controlling means in themanner herein described, in conjunction with such an arrangement ofindependent cooling units as is ,diagrammed in Figure 1, it-is possibleto govern with complete independence the temperature at 1 which eachunit willbe maintained by its valve.

vrelatively to the seat, means connecting the valve member and actuatingmeans, and-temperatureresponsive means for rendering such connectinglmeans ineffective.

2. In an expansion valve, a. valve seat, a valve member' movablerelatively to the seat, actuating means Aincluding a movablepressure-responsive member for governing movement of the valve member,means forming a plurality l of parts4 connecting the valve. member. andactuating means to enable controlling the former bythe latter,and-temperature controllable means for preventing vmovement of one partof said connecting means by another to render said connecting meansineffective at desired times.

4 3. In combination with a circulatory refriger-- ating system includinga plurality of evaporators', an expansion valve for independentlycontrolling the ilow of refrigerant through each evaporator, each valveincluding av valve, seat, a

valve member movable relatively to the seat, a

movable diaphragm member for governing the ing the valve and diaphragmmembers to enable controlling the motivation of the former by thelatter, and means subject to outside control for e.

preventing operation of said .connecting means.

4. In a circulatory refrigerating system including a plurality ofevaporator-s, an expansion valve for controlling the admission ofrefrigerant to each evaporator, each valve including .a valve actuatingof the valve member, means connectf member, a valve seat, apressure-responsiveV member for moving the valve relatively' to itsseat, meansconnecting vthe valve and valve actuating members, and meansfor rendering said connecting means ineective in response totemperatureconditions v temporarily prevailing in the area refrigeratedby the evaporator controlled thereby, comprising a member forming partof said connecting means,4 and movable to break the continuity thereof,means responsive to temperature changes in said area for moving saidmember.

5. In a rerigerating system including an evaporator, an expansion valvecontrolling the admission cf refrigerant to the evaporator, meansnormally responsive to pressure variances in the evaporator foractuating the valve toward opened or closed position, means mechanicallyconnecting the valve and its actuating means, and a member forming partAof the connecting means and controllable in response to varyingtemperature conditions in the refrigerated area for breaking suchmechanical connection to render the pressure-responsive actuating meansinoperative to move the valve.

6. In an expansion valve, a valve member, means for actuating saidvalve, 'means connecting the valve and the actuating member, andtemperature-responsive means for selectively breaking the connectingmeans to render the actuating means ineilective.

7. In combination with a refrigerating system having a cooled zone andan evaporator incorporated therein, an expansion valve membercontrolling the admittance of refrigerant to the evaporator, meansnormallyv responsive to the pressure on one side of the valve foractuating the same toward open or closed position, means connecting thevalve member and actuating means, and means responsive to temperature inthe cooled zone, for rendering the connecting means ineiective underdesired temperature conditions therein.

8. In an expansion valve incorporating a valve member, a valve seat,means adapted to control the opening and closing of the valve, actuatingmeans for the valve, and temperature-responsive means for automaticallyconnecting and disconnecting the valve and its actuating means atdesired times.

9. In an expansion valve, a valve member, a valve seat, apressure-responsive member for moving the valve toward and from itsseat,

means operatively connecting the valve and .l

and closure of said valve are regulated, andmeans operable independentlyof such pressure variations and rponsive to predeterminedtemperaturechanges within the refrigerated space 4served by saidevaporator for positively closing the valve and preventing operationthereof by said pressure-responsive means. A

11. In combination with a circulatory refrigerating system including aplurality of evaporators, a valve appurtenant each evaporator andincluding a valve member, a seat therefor, means for efIecting theopening and closing movement of said valve conformably to variations inrelative pressures within said refrigeration system and meansappurtenant each valve and controllable independentlyof such relativepressures for preventing one of such pressures from inuencing operationof the valve, to thereby enable its positive maintenance in one positionindependently of such pressures. K

12. In combination with a circulatory refrigerating system including aplurality of evaporators, an expansion valve appurtenant each evaporatorand including a valve member and a port relatively-to which the valve ismovable, means subject to the influence of pressure variances actingupon said valve for controllingly so moving the valve member, and meanscontrollable in*v response to temperature conditions in a zone served bythe appurtenant evaporator for lpositively preventing the operation ofthevvalve by such pressure variations and whereby the valve may bemaintained in one position independently thereof.

13. The combination, with a plurality of spaces to be refrigerated, anevaporator in each space and a common circulatory refrigerant systemconnected to all of such evaporators, a pressure-regulated expansionvalve controlling the flow of refrigerant iluid through each`evaporator, means associated with each of said valves for regulating theopening and closure thereof responsively to pressure variations in thesystem, and independent means responsive to thermal conditions withinthe space served by the appurtenant evaporator for rendering saidpressure-responsive means inoperative to control movement of the valve.

14. 'In combination with a common refrigerant supply line and with aplurality of pressure- WILLIAM `C. HILL.

